Epoxidation processes are known. The state of the art comprises for instance Boer de, Johannes W., “cis-Dihydroxylation and Epoxidation of Alkenes by Manganese Catalysts Selectivity, Reactivity and Mechanisms”, University of Groningen, 2008. De Boer describes that it is characteristic for the Manganese Catalysts to show a lag period before full reactivity can be observed. The lag period as described above would result in a time of little reaction in a commercial process. Moreover, this lag period can result in unwanted side-reactions and/or will require extra hold up and/or time consuming treatment of the catalyst before it can be (re)used in the reaction process. The provided invention reduces the lag period to a minimum requiring no pre-treatment or hold up time. Moreover, the provided invention results in a better performing catalyst.